Iron-doped vanadium(v) oxides

Abstract

The present invention relates to iron-doped vanadium(V) oxides of formula Fe y V 2 O 5 , a process for their preparation and their uses as positive electrodes, especially in microbatteries.

1 - 24 . (canceled) 
     
     
         25 . A process for the preparation of a substrate coated with a thin layer of an iron-doped vanadium(V) oxide comprising the steps of:
 a) providing a first Vanadium-containing-target and a second Iron-containing-target and fixing each of said first and second targets on a target-support;   b) positioning said first and second targets in a pulverisation chamber;   c) placing a substrate in the pulverisation chamber facing said two targets;   d) filling the pulverisation chamber with a gas mixture comprising from 0 to about 60-70% of oxygen, and from 30-40 to 100% of argon, until a pressure of about 0.5 Pa to 2 Pa is obtained in the pulverisation chamber;   e) applying an electrical power P V  between the V-target and the substrate and an electrical power P Fe  between the Fe-target and the substrate; and allowing deposition to occur;   f) removing the applied tension, opening the pulverisation chamber and recovering the substrate having a thin layer of iron-doped vanadium(V) oxide on one of its surface.   
     
     
         26 . The process of  claim 25 , wherein said first and second targets are positioned on a target-holder (cathode) in the pulverisation chamber. 
     
     
         27 . The process of  claim 25 , wherein a pressure of the gas mixture of about 1 Pa is obtained in the pulverisation chamber. 
     
     
         28 . The process of  claim 25 , wherein both targets are positioned in the pulverisation chamber in a convergent manner. 
     
     
         29 . The process of  claim 25 , wherein the substrate is placed on a mobile plate. 
     
     
         30 . The process of  claim 25 , wherein the ratio P Fe /P V  ranges from 0.1 to 0.5, and the applied power at the V-target (P V ) is set to a value ranging from 30 W to 70 W, and the applied power at the Fe-target (P Fe ) is set to a value ranging from 5 W to 25 W. 
     
     
         31 . The process of  claim 30 , wherein the ratio P Fe /P V  ranges from 0.2 to 0.4. 
     
     
         32 . The process of  claim 30 , wherein the applied power at the Fe-target (P Fe ) is set to a value ranging from 10 W to 20 W. 
     
     
         33 . The process of  claim 30 , wherein the applied power at the V-target (P V ) is set to a value of about 50 W. 
     
     
         34 . The process of  claim 25 , wherein a pre-pulverisation is carried out before applying said electrical power between the V-target and the substrate and said electrical power between the Fe-target and the substrate. 
     
     
         35 . The process of  claim 25 , said process being carried out at ambient temperature. 
     
     
         36 . Substrate coated with a thin layer of an iron-doped vanadium(V) oxide obtainable by the process according to  claim 25 . 
     
     
         37 . Substrate according to  claim 36 , wherein the iron-doped vanadium(V) oxide has the following formula Fe y V 2 O 5 , wherein y is a positive real number of from 0.03 to 0.8. 
     
     
         38 . Substrate according to  claim 37 , wherein y is a positive real number of from 0.04 to 0.4. 
     
     
         39 . Substrate according to  claim 37 , wherein y is a positive real number of from 0.04 to 0.2. 
     
     
         40 . Substrate according to  claim 36 , wherein the thin layer has a thickness in the range of about 50 nm to about 1000 nm. 
     
     
         41 . Substrate according to  claim 36 , wherein the thin layer has a thickness in the range of about 200 nm to about 800 nm. 
     
     
         42 . Substrate according to  claim 36 , wherein the thin layer has a thickness of about 500 nm. 
     
     
         43 . A microbattery comprising at least one substrate according to  claim 36  as positive electrode. 
     
     
         44 . The microbattery of  claim 43 , further comprising an electrolyte chosen from among lithium borate, lithium oxide, lithium sulphate, lithium phosphate, and the like and mixtures thereof. 
     
     
         45 . The microbattery of  claim 43 , further comprising an electrolyte containing nitrogen. 
     
     
         46 . The microbattery of  claim 44 , wherein the negative electrode is lithium, or lithium together with one or more materials chosen from among carbon, silicon, germanium, tin and any other material able to form an alloy with lithium. 
     
     
         47 . The microbattery of  claim 45 , wherein the iron-doped vanadium(V) oxide is of formula Fe y V 2 O 5 , wherein y is 0.04 or wherein y is 0.19.